There are a variety of apparatuses and methods designed for use in performing carpal tunnel release surgery. Carpal tunnel syndrome is a commonly known problem resulting from compression of the median nerve within the carpal tunnel in the hand which is the name for an anatomic passageway in the wrist and palm. Conditions that crowd or reduce the size of the carpal tunnel and initiate symptoms associated with carpal tunnel syndrome, which is typically characterized by some combination of wrist pain, forearm aching, and/or pain, tingling and numbness in the index and middle fingers as well as the thumb. It is typical for middle-aged people whose jobs necessitate repeated exposure to certain movements and/or vibrating tools, such as those which can be experienced by utilizing computer keyboards, typewriters as well as work which can be associated with assembly lines to experience carpal tunnel syndrome.
It is well known that when carpal tunnel syndrome symptoms become persistent and progressive, division of the deep transverse carpal ligament is often recommended for treatment. A variety of apparatuses and methods for surgically releasing the transverse carpal ligament have been developed and are known in the art. Examples of such apparatuses and methods include, for example, U.S. Pat. No. 5,334,214 to Putnam which discloses a guidance mechanism and cuffing mechanism for subcutaneous insertion in spaced-apart incisions for dividing the transverse carpal ligament. The guidance mechanism is placed below the transverse carpal ligament, and the cutting mechanism is placed above the transverse carpal ligament. The guidance mechanism forms a slot adapted to receive a portion of the cutting mechanism such that as the cuffing mechanism is advanced, it is guided by the guidance mechanism with a portion of the cuffing mechanism sliding through and fitted within the slot of guidance mechanism as a knife portion of the cutting mechanism divides a carpal tunnel ligament.
U.S. Pat. No. 5,387,222 to Strickland discloses a carpal tunnel tome method for performing carpal tunnel release surgery. The disclosed tome includes a slender handle with a blade at one end thereof, with the blade being bounded on both sides by a pair of relatively blunt protuberances extending distally beyond the cutting edge of the blade. The protuberances allow the instrument to straddle a carpal tunnel ligament and serve to protect surrounding tissue during the cutting procedure. Similarly, U.S. Pat. No. 5,507,800, also to Strickland, discloses the carpal tunnel tome disclosed by U.S. Pat. No. 5,387,222, but is directed to coverage of the apparatus itself whereas U.S. Pat. No. 5,387,222 is directed toward coverage of the methodology. In the surgical procedure for the carpal tunnel tome of U.S. Pat. Nos. 5,387,222 and 5,507,800, an incision is initially made in a patient's palm adjacent the distal edge of the transverse carpal ligament. The incision and underlying adipose tissue are then retracted until the distal portion of the transverse carpal ligament becomes visible. Next, the carpal tunnel tome with the blade shielded on its ends by the pair of blunt protuberances projecting away from the blade is positioned in the incision such that the protuberances straddle the transverse carpal ligament and the blade is positioned against the ligament. The carpal tunnel tome is then advanced toward the patient's wrist until the transverse carpal ligament becomes completely divided. Finally, the carpal tunnel tome is withdrawn from the patient, and the incision is typically closed with a few sutures.
U.S. Pat. No. 5,413,580 to Stephenson discloses a similar carpal tunnel knife which includes an elongated shaft with a handle mounted on the rearward end of the shaft and oriented perpendicularly thereto. The forward end of the shaft includes a generally planar blade portion which is oriented perpendicularly with respect to the handle. This blade portion includes a pair of forwardly projecting guide fingers which are separated by a notch, and a cutting edge formed within the notch and extending between the guide fingers.
As illustrated by the exemplary patents described above, a method which is common in the art of carpal tunnel surgery involves making a relatively shorter incision located entirely in the palm and then dividing the deep transverse carpal ligament utilizing a knife which includes protuberances or guide fingers on both sides of the knife. The knife is passed proximately toward a patient's wrist for complete division of the transverse carpal ligament, and this step of cutting the transverse carpal ligament is recognized as causing danger of inadvertent injury to the median nerve or other structures within the hand as the knife is passed proximately during the cutting method.
In view of the above, and despite the existence of a variety of apparatuses and methods for carpal tunnel release surgery, there remains much room for improvement in the art, particularly for a carpal tunnel release apparatus and method which is simple, safe and effective for complete division of the transverse carpal ligament in an effort to minimize pain and recovery time.